The present invention is directed to the field of machining of parts. More particularly, the present invention is directed to a workpiece stabilizer useful with multiple jaw chucks.
In machining operations, multiple jaw chucks in lathes and the like, are very useful for a variety of operations. However, operations on certain types of articles are difficult and some type of stabilizer is required. One such application is when turning a relatively thin disk. Application of force by the cutter can cause the disk to cant in the jaws potentially damaging the workpiece as well as the cutter. A similar problem can arise when turning a cylindrical bar: the bar can slip linearly in the jaws such that the proper machining cannot be accomplished.
The stabilizer of the present invention engages a disk-shaped workpiece at three locations on the rear face thereof ensuring its proper alignment throughout the machining operation. In a like manner a single stop engages the end of a cylindrical workpiece and maintains it in its proper axial position as it is machined. The stabilizer of the present invention comprises a generally cylindrical body portion at least partially insertable in a central aperture in the chuck, the body portion having a first end, a second end, and a side wall extending between the first end and the second end, openings being formed in the side wall to form thin-walled regions there between; an aperture extending through the length of the body portion, at least a portion of which is internally threaded; a cylindrical rod being at least partially threaded on its exterior surface with a thread compatible with the internally threaded portion of the aperture; at least one member having a stabilizing surface for engaging the workpiece as it is held in the multi-jaw chuck to prevent its axial movement during machining; a nut having an internally threaded surface which receives the cylindrical rod, expander means having a tapered outer surface, at least a portion of which is received within said aperture; whereby when said nut is tightened upon said cylindrical rod in said aperture, said expander means causes said thin-walled regions to flex outwardly securing said body portion within the central opening of the multi jaw chuck.
More preferably, in one application, the at least one member comprises the cylindrical rod with the stabilizing surface being an end portion which projects outwardly beyond an outer surface of the nut. In a second application, the at least one member comprises at least three members engaging a face of a disk being held by the multiple jaw chuck for machining by a lathe. Each of the at least three members comprises a head of a cap screw radially adjustable by threading into one of a plurality threaded openings in each of three radially extending arms which are threadingly attached to a head portion formed on the generally cylindrical body by an outwardly extending flange formed on a second side of the body distal from the first side which is received in the central aperture in the chuck. The axial position of each of the three members is adjusted by threading each cap screw a greater or lesser amount into one of the plurality of openings. The stabilizer preferably includes a lock nut on each of the cap screws to maintain its axially adjusted position. The stabilizer also preferably comprises three equally spaced lobes connected at the second end and being subdivided into three equal portions at the first end, whereby when the nut is tightened on the threaded rod, the tapered portion thereof flexes the thin-walled regions mounting the three equally spaced lobes outwardly into secure engagement within the central opening of the chuck.
In a first embodiment, the expander means comprises a tapered outer surface on a lead portion of the nut. In a second embodiment, the expander means comprises a cylindrical sleeve having a first outer diameter, a collar having a second greater outer diameter and the tapered outer surface being formed as a transitional zone between the cylindrical sleeve and the collar. In this second embodiment, the expander means further comprises complimentary surfaces formed within the cylindrical body portion interacting with the tapered outer surface of the transitional zone.
Various other features, advantages, and characteristics of the present invention will become apparent after a reading of the following detailed description.